root/trunk/lisp/calc/calc-sel.el

;;; calc-sel.el --- data selection functions for Calc

;; Copyright (C) 1990, 1991, 1992, 1993, 2001, 2002, 2003, 2004,
;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc.

;; Author: David Gillespie <daveg@synaptics.com>
;; Maintainer: Jay Belanger <jay.p.belanger@gmail.com>

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 3, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;;; Code:

;; This file is autoloaded from calc-ext.el.

(require 'calc-ext)
(require 'calc-macs)

;;; Selection commands.

(defvar calc-keep-selection t)

(defvar calc-selection-cache-entry nil)
(defvar calc-selection-cache-num)
(defvar calc-selection-cache-comp)
(defvar calc-selection-cache-offset)
(defvar calc-selection-true-num)

(defun calc-select-here (num &optional once keep)
  (interactive "P")
  (calc-wrapper
   (calc-prepare-selection)
   (let ((found (calc-find-selected-part))
         (entry calc-selection-cache-entry))
     (or (and keep (nth 2 entry))
         (progn
           (if once (progn
                      (setq calc-keep-selection nil)
                      (message "(Selection will apply to next command only)")))
           (calc-change-current-selection
            (if found
                (if (and num (> (setq num (prefix-numeric-value num)) 0))
                    (progn
                      (while (and (>= (setq num (1- num)) 0)
                                  (not (eq found (car entry))))
                        (setq found (calc-find-assoc-parent-formula
                                     (car entry) found)))
                      found)
                  (calc-grow-assoc-formula (car entry) found))
              (car entry))))))))

(defun calc-select-once (num)
  (interactive "P")
  (calc-select-here num t))

(defun calc-select-here-maybe (num)
  (interactive "P")
  (calc-select-here num nil t))

(defun calc-select-once-maybe (num)
  (interactive "P")
  (calc-select-here num t t))

(defun calc-select-additional ()
  (interactive)
  (calc-wrapper
   (let (calc-keep-selection)
     (calc-prepare-selection))
   (let ((found (calc-find-selected-part))
         (entry calc-selection-cache-entry))
     (calc-change-current-selection
      (if found
          (let ((sel (nth 2 entry)))
            (if sel
                (progn
                  (while (not (or (eq sel (car entry))
                                  (calc-find-sub-formula sel found)))
                    (setq sel (calc-find-assoc-parent-formula
                               (car entry) sel)))
                  sel)
              (calc-grow-assoc-formula (car entry) found)))
        (car entry))))))

(defun calc-select-more (num)
  (interactive "P")
  (calc-wrapper
   (calc-prepare-selection)
   (let ((entry calc-selection-cache-entry))
     (if (nth 2 entry)
         (let ((sel (nth 2 entry)))
           (while (and (not (eq sel (car entry)))
                       (>= (setq num (1- (prefix-numeric-value num))) 0))
             (setq sel (calc-find-assoc-parent-formula (car entry) sel)))
           (calc-change-current-selection sel))
       (calc-select-here num)))))

(defun calc-select-less (num)
  (interactive "p")
  (calc-wrapper
   (calc-prepare-selection)
   (let ((found (calc-find-selected-part))
         (entry calc-selection-cache-entry))
     (calc-change-current-selection
      (and found
           (let ((sel (nth 2 entry))
                 old index op)
             (while (and sel
                         (not (eq sel found))
                         (>= (setq num (1- num)) 0))
               (setq old sel
                     index (calc-find-sub-formula sel found))
               (and (setq sel (and index (nth index old)))
                    calc-assoc-selections
                    (setq op (assq (car-safe sel) calc-assoc-ops))
                    (memq (car old) (nth index op))
                    (setq num (1+ num))))
             sel))))))

(defun calc-select-part (num)
  (interactive "P")
  (or num (setq num (- last-command-char ?0)))
  (calc-wrapper
   (calc-prepare-selection)
   (let ((sel (calc-find-nth-part (or (nth 2 calc-selection-cache-entry)
                                      (car calc-selection-cache-entry))
                                  num)))
     (if sel
         (calc-change-current-selection sel)
       (error "%d is not a valid sub-formula index" num)))))

;; The variables calc-fnp-op and calc-fnp-num are local to 
;; calc-find-nth-part (and calc-select-previous) but used by 
;; calc-find-nth-part-rec, which is called by them.
(defvar calc-fnp-op)
(defvar calc-fnp-num)

(defun calc-find-nth-part (expr calc-fnp-num)
  (if (and calc-assoc-selections
           (assq (car-safe expr) calc-assoc-ops))
      (let (calc-fnp-op)
        (calc-find-nth-part-rec expr))
    (if (eq (car-safe expr) 'intv)
        (and (>= calc-fnp-num 1) (<= calc-fnp-num 2) (nth (1+ calc-fnp-num) expr))
      (and (not (Math-primp expr)) (>= calc-fnp-num 1) (< calc-fnp-num (length expr))
           (nth calc-fnp-num expr)))))

(defun calc-find-nth-part-rec (expr)   ; uses num, op
  (or (if (and (setq calc-fnp-op (assq (car-safe (nth 1 expr)) calc-assoc-ops))
               (memq (car expr) (nth 1 calc-fnp-op)))
          (calc-find-nth-part-rec (nth 1 expr))
        (and (= (setq calc-fnp-num (1- calc-fnp-num)) 0)
             (nth 1 expr)))
      (if (and (setq calc-fnp-op (assq (car-safe (nth 2 expr)) calc-assoc-ops))
               (memq (car expr) (nth 2 calc-fnp-op)))
          (calc-find-nth-part-rec (nth 2 expr))
        (and (= (setq calc-fnp-num (1- calc-fnp-num)) 0)
             (nth 2 expr)))))

(defun calc-select-next (num)
  (interactive "p")
  (if (< num 0)
      (calc-select-previous (- num))
    (calc-wrapper
     (calc-prepare-selection)
     (let* ((entry calc-selection-cache-entry)
            (sel (nth 2 entry)))
       (if sel
           (progn
             (while (>= (setq num (1- num)) 0)
               (let* ((parent (calc-find-parent-formula (car entry) sel))
                     (p parent)
                     op)
                 (and (eq p t) (setq p nil))
                 (while (and (setq p (cdr p))
                             (not (eq (car p) sel))))
                 (if (cdr p)
                     (setq sel (or (and calc-assoc-selections
                                        (setq op (assq (car-safe (nth 1 p))
                                                       calc-assoc-ops))
                                        (memq (car parent) (nth 2 op))
                                        (nth 1 (nth 1 p)))
                                   (nth 1 p)))
                   (if (and calc-assoc-selections
                            (setq op (assq (car-safe parent) calc-assoc-ops))
                            (consp (setq p (calc-find-parent-formula
                                            (car entry) parent)))
                            (eq (nth 1 p) parent)
                            (memq (car p) (nth 1 op)))
                       (setq sel (nth 2 p))
                     (error "No \"next\" sub-formula")))))
             (calc-change-current-selection sel))
         (if (Math-primp (car entry))
             (calc-change-current-selection (car entry))
           (calc-select-part num)))))))

(defun calc-select-previous (num)
  (interactive "p")
  (if (< num 0)
      (calc-select-next (- num))
    (calc-wrapper
     (calc-prepare-selection)
     (let* ((entry calc-selection-cache-entry)
            (sel (nth 2 entry)))
       (if sel
           (progn
             (while (>= (setq num (1- num)) 0)
               (let* ((parent (calc-find-parent-formula (car entry) sel))
                      (p (cdr-safe parent))
                      (prev nil)
                      op)
                 (if (eq (car-safe parent) 'intv) (setq p (cdr p)))
                 (while (and (not (eq (car p) sel))
                             (setq prev (car p)
                                   p (cdr p))))
                 (if prev
                     (setq sel (or (and calc-assoc-selections
                                        (setq op (assq (car-safe prev)
                                                       calc-assoc-ops))
                                        (memq (car parent) (nth 1 op))
                                        (nth 2 prev))
                                   prev))
                   (if (and calc-assoc-selections
                            (setq op (assq (car-safe parent) calc-assoc-ops))
                            (consp (setq p (calc-find-parent-formula
                                            (car entry) parent)))
                            (eq (nth 2 p) parent)
                            (memq (car p) (nth 2 op)))
                       (setq sel (nth 1 p))
                     (error "No \"previous\" sub-formula")))))
             (calc-change-current-selection sel))
         (if (Math-primp (car entry))
             (calc-change-current-selection (car entry))
           (let ((len (if (and calc-assoc-selections
                               (assq (car (car entry)) calc-assoc-ops))
                          (let (calc-fnp-op (calc-fnp-num 0))
                            (calc-find-nth-part-rec (car entry))
                            (- 1 calc-fnp-num))
                        (length (car entry)))))
             (calc-select-part (- len num)))))))))

(defun calc-find-parent-formula (expr part)
  (cond ((eq expr part) t)
        ((Math-primp expr) nil)
        (t
         (let ((p expr) res)
           (while (and (setq p (cdr p))
                       (not (setq res (calc-find-parent-formula
                                       (car p) part)))))
           (and p
                (if (eq res t) expr res))))))


(defun calc-find-assoc-parent-formula (expr part)
  (calc-grow-assoc-formula expr (calc-find-parent-formula expr part)))

(defun calc-grow-assoc-formula (expr part)
  (if calc-assoc-selections
      (let ((op (assq (car-safe part) calc-assoc-ops)))
        (if op
            (let (new)
              (while (and (consp (setq new (calc-find-parent-formula
                                            expr part)))
                          (memq (car new)
                                (nth (calc-find-sub-formula new part) op)))
                (setq part new))))
        part)
    part))

(defun calc-find-sub-formula (expr part)
  (cond ((eq expr part) t)
        ((Math-primp expr) nil)
        (t
         (let ((num 1))
           (while (and (setq expr (cdr expr))
                       (not (calc-find-sub-formula (car expr) part)))
             (setq num (1+ num)))
           (and expr num)))))

(defun calc-unselect (num)
  (interactive "P")
  (calc-wrapper
   (calc-prepare-selection num)
   (calc-change-current-selection nil)))

(defun calc-clear-selections ()
  (interactive)
  (calc-wrapper
   (let ((limit (calc-stack-size))
         (n 1))
     (while (<= n limit)
       (if (calc-top n 'sel)
           (progn
             (calc-prepare-selection n)
             (calc-change-current-selection nil)))
       (setq n (1+ n))))
   (calc-clear-command-flag 'position-point)))

(defun calc-show-selections (arg)
  (interactive "P")
  (calc-wrapper
   (calc-preserve-point)
   (setq calc-show-selections (if arg
                                  (> (prefix-numeric-value arg) 0)
                                (not calc-show-selections)))
   (let ((p calc-stack))
     (while (and p
                 (or (null (nth 2 (car p)))
                     (equal (car p) calc-selection-cache-entry)))
       (setq p (cdr p)))
     (or (and p
              (let ((calc-selection-cache-default-entry
                     calc-selection-cache-entry))
                (calc-do-refresh)))
         (and calc-selection-cache-entry
              (let ((sel (nth 2 calc-selection-cache-entry)))
                (setcar (nthcdr 2 calc-selection-cache-entry) nil)
                (calc-change-current-selection sel)))))
   (message (if calc-show-selections
                "Displaying only selected part of formulas"
              "Displaying all but selected part of formulas"))))

;; The variables calc-final-point-line and calc-final-point-column
;; are declared in calc.el, and are used throughout.
(defvar calc-final-point-line)
(defvar calc-final-point-column)

(defun calc-preserve-point ()
  (or (looking-at "\\.\n+\\'")
      (progn
        (setq calc-final-point-line (+ (count-lines (point-min) (point))
                                       (if (bolp) 1 0))
              calc-final-point-column (current-column))
        (calc-set-command-flag 'position-point))))

(defun calc-enable-selections (arg)
  (interactive "P")
  (calc-wrapper
   (calc-preserve-point)
   (setq calc-use-selections (if arg
                                 (> (prefix-numeric-value arg) 0)
                               (not calc-use-selections)))
   (calc-set-command-flag 'renum-stack)
   (message (if calc-use-selections
                "Commands operate only on selected sub-formulas"
              "Selections of sub-formulas have no effect"))))

(defun calc-break-selections (arg)
  (interactive "P")
  (calc-wrapper
   (calc-preserve-point)
   (setq calc-assoc-selections (if arg
                                   (<= (prefix-numeric-value arg) 0)
                                 (not calc-assoc-selections)))
   (message (if calc-assoc-selections
                "Selection treats a+b+c as a sum of three terms"
              "Selection treats a+b+c as (a+b)+c"))))

(defun calc-prepare-selection (&optional num)
  (or num (setq num (calc-locate-cursor-element (point))))
  (setq calc-selection-true-num num
        calc-keep-selection t)
  (or (> num 0) (setq num 1))
  ;; (if (or (< num 1) (> num (calc-stack-size)))
  ;;     (error "Cursor must be positioned on a stack element"))
  (let* ((entry (calc-top num 'entry))
         ww w)
    (or (equal entry calc-selection-cache-entry)
        (progn
          (setcar entry (calc-encase-atoms (car entry)))
          (setq calc-selection-cache-entry entry
                calc-selection-cache-num num
                calc-selection-cache-comp
                (let ((math-comp-tagged t))
                  (math-compose-expr (car entry) 0))
                calc-selection-cache-offset
                (+ (car (math-stack-value-offset calc-selection-cache-comp))
                   (length calc-left-label)
                   (if calc-line-numbering 4 0))))))
  (calc-preserve-point))

;;; The following ensures that no two subformulas will be "eq" to each other!
(defun calc-encase-atoms (x)
  (if (or (not (consp x))
          (equal x '(float 0 0)))
      (list 'cplx x 0)
    (calc-encase-atoms-rec x)
    x))

(defun calc-encase-atoms-rec (x)
  (or (Math-primp x)
      (progn
        (if (eq (car x) 'intv)
            (setq x (cdr x)))
        (while (setq x (cdr x))
          (if (or (not (consp (car x)))
                  (equal (car x) '(float 0 0)))
              (setcar x (list 'cplx (car x) 0))
            (calc-encase-atoms-rec (car x)))))))

;; The variable math-comp-sel-tag is local to calc-find-selected-part,
;; but is used by math-comp-sel-flat-term and math-comp-add-string-sel
;; in calccomp.el, which are called (indirectly) by calc-find-selected-part.

(defun calc-find-selected-part ()
  (let* ((math-comp-sel-hpos (- (current-column) calc-selection-cache-offset))
         toppt
         (lcount 0)
         (spaces 0)
         (math-comp-sel-vpos (save-excursion
                               (beginning-of-line)
                               (let ((line (point)))
                                 (calc-cursor-stack-index
                                  calc-selection-cache-num)
                                 (setq toppt (point))
                                 (while (< (point) line)
                                   (forward-line 1)
                                   (setq spaces (+ spaces
                                                   (current-indentation))
                                         lcount (1+ lcount)))
                                 (- lcount (math-comp-ascent
                                            calc-selection-cache-comp) -1))))
         (math-comp-sel-cpos (- (point) toppt calc-selection-cache-offset
                                spaces lcount))
         (math-comp-sel-tag nil))
    (and (>= math-comp-sel-hpos 0)
         (> calc-selection-true-num 0)
         (math-composition-to-string calc-selection-cache-comp 1000000))
    (nth 1 math-comp-sel-tag)))

(defun calc-change-current-selection (sub-expr)
  (or (eq sub-expr (nth 2 calc-selection-cache-entry))
      (let ((calc-prepared-composition calc-selection-cache-comp)
            (buffer-read-only nil)
            top)
        (calc-set-command-flag 'renum-stack)
        (setcar (nthcdr 2 calc-selection-cache-entry) sub-expr)
        (calc-cursor-stack-index calc-selection-cache-num)
        (setq top (point))
        (calc-cursor-stack-index (1- calc-selection-cache-num))
        (delete-region top (point))
        (let ((calc-selection-cache-default-entry calc-selection-cache-entry))
          (insert (math-format-stack-value calc-selection-cache-entry)
                  "\n")))))

(defun calc-top-selected (&optional n m)
  (and calc-any-selections
       calc-use-selections
       (progn
         (or n (setq n 1))
         (or m (setq m 1))
         (calc-check-stack (+ n m -1))
         (let ((top (nthcdr (+ m calc-stack-top -1) calc-stack))
               (sel nil))
           (while (>= (setq n (1- n)) 0)
             (if (nth 2 (car top))
                 (setq sel (if sel t (nth 2 (car top)))))
             (setq top (cdr top)))
           sel))))

;; The variables calc-rsf-old and calc-rsf-new are local to
;; calc-replace-sub-formula, but used by calc-replace-sub-formula-rec,
;; which is called by calc-replace-sub-formula.
(defvar calc-rsf-old)
(defvar calc-rsf-new)

(defun calc-replace-sub-formula (expr calc-rsf-old calc-rsf-new)
  (setq calc-rsf-new (calc-encase-atoms calc-rsf-new))
  (calc-replace-sub-formula-rec expr))

(defun calc-replace-sub-formula-rec (expr)
  (cond ((eq expr calc-rsf-old) calc-rsf-new)
        ((Math-primp expr) expr)
        (t
         (cons (car expr)
               (mapcar 'calc-replace-sub-formula-rec (cdr expr))))))

(defun calc-sel-error ()
  (error "Invalid operation on sub-formulas"))

(defun calc-replace-selections (n vals m)
  (if (calc-top-selected n m)
      (let ((num (length vals)))
        (calc-preserve-point)
        (cond
         ((= n num)
          (let* ((old (calc-top-list n m 'entry))
                 (new nil)
                 (sel nil)
                 val)
            (while old
              (if (nth 2 (car old))
                  (setq val (calc-encase-atoms (car vals))
                        new (cons (calc-replace-sub-formula (car (car old))
                                                            (nth 2 (car old))
                                                            val)
                                  new)
                        sel (cons val sel))
                (setq new (cons (car vals) new)
                      sel (cons nil sel)))
              (setq vals (cdr vals)
                    old (cdr old)))
            (calc-pop-stack n m t)
            (calc-push-list (nreverse new)
                            m (and calc-keep-selection (nreverse sel)))))
         ((= num 1)
          (let* ((old (calc-top-list n m 'entry))
                 more)
            (while (and old (not (nth 2 (car old))))
              (setq old (cdr old)))
            (setq more old)
            (while (and (setq more (cdr more)) (not (nth 2 (car more)))))
            (and more
                 (calc-sel-error))
            (calc-pop-stack n m t)
            (if old
                (let ((val (calc-encase-atoms (car vals))))
                  (calc-push-list (list (calc-replace-sub-formula
                                         (car (car old))
                                         (nth 2 (car old))
                                         val))
                                  m (and calc-keep-selection (list val))))
              (calc-push-list vals))))
         (t (calc-sel-error))))
    (calc-pop-stack n m t)
    (calc-push-list vals m)))

(defun calc-delete-selection (n)
  (let ((entry (calc-top n 'entry)))
    (if (nth 2 entry)
        (if (eq (nth 2 entry) (car entry))
            (progn
              (calc-pop-stack 1 n t)
              (calc-push-list '(0) n))
          (let ((parent (calc-find-parent-formula (car entry) (nth 2 entry)))
                (repl nil))
            (calc-preserve-point)
            (calc-pop-stack 1 n t)
            (cond ((or (memq (car parent) '(* / %))
                       (and (eq (car parent) '^)
                            (eq (nth 2 parent) (nth 2 entry))))
                   (setq repl 1))
                  ((memq (car parent) '(vec calcFunc-min calcFunc-max)))
                  ((and (assq (car parent) calc-tweak-eqn-table)
                        (= (length parent) 3))
                   (setq repl 'del))
                  (t
                   (setq repl 0)))
            (cond
             ((eq repl 'del)
              (calc-push-list (list
                               (calc-normalize
                                (calc-replace-sub-formula
                                 (car entry)
                                 parent
                                 (if (eq (nth 2 entry) (nth 1 parent))
                                     (nth 2 parent)
                                   (nth 1 parent)))))
                              n))
             (repl
              (calc-push-list (list
                               (calc-normalize
                                (calc-replace-sub-formula (car entry)
                                                          (nth 2 entry)
                                                          repl)))
                              n))
             (t
              (calc-push-list (list
                               (calc-normalize
                                (calc-replace-sub-formula (car entry)
                                                          parent
                                                          (delq (nth 2 entry)
                                                                (copy-sequence
                                                                 parent)))))
                              n)))))
      (calc-pop-stack 1 n t))))

(defun calc-roll-down-with-selections (n m)
  (let ((vals (append (calc-top-list m 1)
                      (calc-top-list (- n m) (1+ m))))
        (sels (append (calc-top-list m 1 'sel)
                      (calc-top-list (- n m) (1+ m) 'sel))))
    (calc-pop-push-list n vals 1 sels)))

(defun calc-roll-up-with-selections (n m)
  (let ((vals (append (calc-top-list (- n m) 1)
                      (calc-top-list m (- n m -1))))
        (sels (append (calc-top-list (- n m) 1 'sel)
                      (calc-top-list m (- n m -1) 'sel))))
    (calc-pop-push-list n vals 1 sels)))

;; The variable calc-sel-reselect is local to several functions
;; which call calc-auto-selection.
(defvar calc-sel-reselect)

(defun calc-auto-selection (entry)
  (or (nth 2 entry)
      (progn
        (setq calc-sel-reselect nil)
        (calc-prepare-selection)
        (calc-grow-assoc-formula (car entry) (calc-find-selected-part)))))

(defun calc-copy-selection ()
  (interactive)
  (calc-wrapper
   (calc-preserve-point)
   (let* ((num (max 1 (calc-locate-cursor-element (point))))
          (entry (calc-top num 'entry)))
     (calc-push (or (calc-auto-selection entry) (car entry))))))

(defun calc-del-selection ()
  (interactive)
  (calc-wrapper
   (calc-preserve-point)
   (let* ((num (max 1 (calc-locate-cursor-element (point))))
          (entry (calc-top num 'entry))
          (sel (calc-auto-selection entry)))
     (setcar (nthcdr 2 entry) (and (not (eq sel (car entry))) sel))
     (calc-delete-selection num))))

(defvar calc-selection-history nil
  "History for calc selections.")

(defun calc-enter-selection ()
  (interactive)
  (calc-wrapper
   (calc-preserve-point)
   (let* ((num (max 1 (calc-locate-cursor-element (point))))
          (calc-sel-reselect calc-keep-selection)
          (entry (calc-top num 'entry))
          (expr (car entry))
          (sel (or (calc-auto-selection entry) expr))
          alg)
     (let ((calc-dollar-values (list sel))
           (calc-dollar-used 0))
       (setq alg (calc-do-alg-entry "" "Replace selection with: " nil 
                                    'calc-selection-history))
       (and alg
            (progn
              (setq alg (calc-encase-atoms (car alg)))
              (calc-pop-push-record-list 1 "repl"
                                         (list (calc-replace-sub-formula
                                                expr sel alg))
                                         num
                                         (list (and calc-sel-reselect alg))))))
     (calc-handle-whys))))

(defun calc-edit-selection ()
  (interactive)
  (calc-wrapper
   (calc-preserve-point)
   (let* ((num (max 1 (calc-locate-cursor-element (point))))
          (calc-sel-reselect calc-keep-selection)
          (entry (calc-top num 'entry))
          (expr (car entry))
          (sel (or (calc-auto-selection entry) expr))
          alg)
     (let ((str (math-showing-full-precision
                 (math-format-nice-expr sel (frame-width)))))
       (calc-edit-mode (list 'calc-finish-selection-edit
                             num (list 'quote sel) calc-sel-reselect))
       (insert str "\n"))))
  (calc-show-edit-buffer))

(defvar calc-original-buffer)

;; The variable calc-edit-disp-trail is local to calc-edit-finish,
;; in calc-yank.el.
(defvar calc-edit-disp-trail)
(defvar calc-edit-top)

(defun calc-finish-selection-edit (num sel reselect)
  (let ((buf (current-buffer))
        (str (buffer-substring calc-edit-top (point-max)))
        (start (point)))
    (switch-to-buffer calc-original-buffer)
    (let ((val (math-read-expr str)))
      (if (eq (car-safe val) 'error)
          (progn
            (switch-to-buffer buf)
            (goto-char (+ start (nth 1 val)))
            (error (nth 2 val))))
      (calc-wrapper
       (calc-preserve-point)
       (if calc-edit-disp-trail
           (calc-trail-display 1 t))
       (setq val (calc-encase-atoms (calc-normalize val)))
       (let ((expr (calc-top num 'full)))
         (if (calc-find-sub-formula expr sel)
             (calc-pop-push-record-list 1 "edit"
                                        (list (calc-replace-sub-formula
                                               expr sel val))
                                        num
                                        (list (and reselect val)))
           (calc-push val)
           (error "Original selection has been lost")))))))

(defun calc-sel-evaluate (arg)
  (interactive "p")
  (calc-slow-wrapper
   (calc-preserve-point)
   (let* ((num (max 1 (calc-locate-cursor-element (point))))
          (calc-sel-reselect calc-keep-selection)
          (entry (calc-top num 'entry))
          (sel (or (calc-auto-selection entry) (car entry))))
     (calc-with-default-simplification
      (let ((math-simplify-only nil))
        (calc-modify-simplify-mode arg)
        (let ((val (calc-encase-atoms (calc-normalize sel))))
          (calc-pop-push-record-list 1 "jsmp"
                                     (list (calc-replace-sub-formula
                                            (car entry) sel val))
                                     num
                                     (list (and calc-sel-reselect val))))))
     (calc-handle-whys))))

(defun calc-sel-expand-formula (arg)
  (interactive "p")
  (calc-slow-wrapper
   (calc-preserve-point)
   (let* ((num (max 1 (calc-locate-cursor-element (point))))
          (calc-sel-reselect calc-keep-selection)
          (entry (calc-top num 'entry))
          (sel (or (calc-auto-selection entry) (car entry))))
     (calc-with-default-simplification
      (let ((math-simplify-only nil))
        (calc-modify-simplify-mode arg)
        (let* ((math-expand-formulas (> arg 0))
               (val (calc-normalize sel))
               top)
          (and (<= arg 0)
               (setq top (math-expand-formula val))
               (setq val (calc-normalize top)))
          (setq val (calc-encase-atoms val))
          (calc-pop-push-record-list 1 "jexf"
                                     (list (calc-replace-sub-formula
                                            (car entry) sel val))
                                     num
                                     (list (and calc-sel-reselect val))))))
     (calc-handle-whys))))

(defun calc-sel-mult-both-sides (no-simp &optional divide)
  (interactive "P")
  (calc-wrapper
   (calc-preserve-point)
   (let* ((num (max 1 (calc-locate-cursor-element (point))))
          (calc-sel-reselect calc-keep-selection)
          (entry (calc-top num 'entry))
          (expr (car entry))
          (sel (or (calc-auto-selection entry) expr))
          (func (car-safe sel))
          alg lhs rhs)
     (setq alg (calc-with-default-simplification
                (car (calc-do-alg-entry ""
                                        (if divide
                                            "Divide both sides by: "
                                          "Multiply both sides by: ")
                                        nil 'calc-selection-history))))
     (and alg
          (progn
            (if (and (or (eq func '/)
                         (assq func calc-tweak-eqn-table))
                     (= (length sel) 3))
                (progn
                  (or (memq func '(/ calcFunc-eq calcFunc-neq))
                      (if (math-known-nonposp alg)
                          (progn
                            (setq func (nth 1 (assq func
                                                    calc-tweak-eqn-table)))
                            (or (math-known-negp alg)
                                (message "Assuming this factor is nonzero")))
                        (or (math-known-posp alg)
                            (if (math-known-nonnegp alg)
                                (message "Assuming this factor is nonzero")
                              (message "Assuming this factor is positive")))))
                  (setq lhs (list (if divide '/ '*) (nth 1 sel) alg)
                        rhs (list (if divide '/ '*) (nth 2 sel) alg))
                  (or no-simp
                      (progn
                        (setq lhs (math-simplify lhs)
                              rhs (math-simplify rhs))
                        (and (eq func '/)
                             (or (Math-equal (nth 1 sel) 1)
                                 (Math-equal (nth 1 sel) -1)
                                 (and (memq (car-safe (nth 2 sel)) '(+ -))
                                      (memq (car-safe alg) '(+ -))))
                             (setq rhs (math-expand-term rhs)))))
                  (setq alg (calc-encase-atoms
                             (calc-normalize (list func lhs rhs)))))
              (setq rhs (list (if divide '* '/) sel alg))
              (or no-simp
                  (setq rhs (math-simplify rhs)))
              (setq alg (calc-encase-atoms
          &nbs